Seatback frame



FIG. 1 is a front view of the seatback frame;

FIG. 2 is a rear view of the seatback frame;

FIG. 3 is a left view of the seatback frame;

FIG. 4 is a right view of the seatback frame;

FIG. 5 is a top view of the seatback frame;

FIG. 6 is a bottom view of the seatback frame; and,

FIG. 7 is a perspective view of the seatback frame. 

The ornamental design for a seatback frame, as shown and described. 